File Uploader, Needing to fix to upload multi files

[livelong]

I need help! I have every thing how I want it but, I can't seem to add extra files to upload.

I am not sure how to alter this

 

Html:

 

<form enctype="multipart/form-data" method="post" action="upload_file.php">
<input type="hidden" name="MAX_FILE_SIZE" value="2500000000">

<p><strong>File to Upload:</strong><br>
<input type="file" name="our_file" size="30"></p>

<P><input type="submit" name="submit" value="Upload File"></p>

</form>

 

PHP:

 

<?

if ($our_file != "") {

copy($our_file, "upload/$our_file_name") or die("Couldn't Upload the file!");  

} else {

die("No input file specified");
}

?>